Arnold, Paul DanielMacMaster, Frank P.Corrigan, Kimberly2019-09-062019-09-062019-09-04Corrigan, K. (2019). Examining the Relationship Between Obsessive-Compulsive Symptoms, Genetic Risk and Cortical Thickness in Youth (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.http://hdl.handle.net/1880/110872Obsessive-compulsive disorder (OCD) is a disabling neuropsychiatric disorder that affects approximately 1-3% of the population worldwide. One-third to one-half of individuals with OCD have symptom onset before 15 years of age. The heterogeneous clinical expression of OCD has rendered inconsistent findings from structural imaging studies with small sample sizes. Large scale structural imaging studies are needed to better understand the complicated neurobiology of OCD in child and adolescent population. To assess brain structure, magnetic resonance imaging (MRI) was used. FreeSurfer (Version 6.0) recon-all pathway was used to determine cortical thickness. The cingulate cortex, orbitofrontal cortex and insular cortex were selected as regions of interest. A candidate gene analysis of PTPRD SNP rs7856850 was performed using Illumina Multi-Ethnic Global microarray. Obsessive-compulsive symptom severity was determined using the Child Behaviour Checklist Obsessive-Compulsive Scale (CBCL-OCS). A significant relationship was found between the current CBCL-OCS score and the right posterior cingulate. Increase in symptom severity on the current CBCL-OCS predicted an increase in cortical thickness of the right posterior cingulate. Rs7856850 genotype did not significantly modify the relationship between symptom severity and right posterior cingulate thickness. This a unique large scale pediatric imaging study investigating the association between obsessive-compulsive symptoms and cortical thickness with an additional exploration of a PTPRD SNP variant. The results support the concept that the posterior cingulate is involved in the pathophysiology of OCD. The candidate gene analysis was inconclusive but hopefully, this study will encourage more research in the neurobiology of youth OCD.engUniversity of Calgary graduate students retain copyright ownership and moral rights for their thesis. You may use this material in any way that is permitted by the Copyright Act or through licensing that has been assigned to the document. For uses that are not allowable under copyright legislation or licensing, you are required to seek permission.child; adolescent; youth; obsessive-compulsive; neuroimaging, cortical thickness, candidate gene; PTPRDGeneticsNeuroscienceMental Healthmaster thesis10.11575/PRISM/36950